The present invention relates to a method of holding, or keeping a multitude of individual optical fibers together which are located parallel to and at each other forming a flat structure, so called ribbonized optical fibers, to form a united ribbon structure, further to an adhesive tape to form such a united ribbon structure and to a device for placing the adhesive tape to keep a multitude of optical fibers together.
In the fiberoptical communication technical field, to a wider and wider extent, in addition to loose optical fibers, optical ribbon fibers or xe2x80x9cribbonsxe2x80x9d are used, i.e. optical fibers which by an exterior means such as a polymer sleeve are kept together to form a unit of type ribbon cable, i.e. a flat fiber package consisting of a number of parallel optical fibers. Typical numbers can be 4, 6, 82 or 12 fibers in a ribbon fiber. When splicing optical fibers and ribbon fibers often welding is used. A splice can in principle be made between individual optical fibers, between ribbon fibers and between ribbon fibers and individual optical fibers. The latter operation can be a complex, labour consuming and time demanding procedure including much manual handling which naturally is costly. Devices for facilitating the handling of loose fibers in such splicing operations have been proposed, see for example the published European patent application 95850079.5 and the corresponding U.S. Pat. No. 5,586,211. In such devices the loose optical fibers can be placed in a narrow slot pressed to each other, so that they are placed in the same way as the individual optical fibers in a ribbon fiber. The fibers can in this state be clamped by a detachable fiber retainer or fiber holder which together with the fibers can be moved to a welding device. Splicing such fibers composed to an assembly can be made in a relatively simple way and relatively fast in welding devices intended for splicing ribbon fibers compared to splicing only one fiber at a time. However, the fiber retainer is a relatively unwieldy metal part which is not suitable for all handling.
In the published British patent application 2 187 865 an optical ribbon cable is disclosed which has a number of parallel optical fibers located at each other, the optical fibers being joined by e.g. strips of a plastics material.
It is an object of the invention to provide methods and means for more or less permanently keeping loose optical fibers tog ether which are arranged in a parallel structure to form a unit similar to a ribbon fiber.
It is a further object of the invention to provide means for comfortably handling loose optical fibers which are arranged in a parallel structure, such as for moving the optical fibers to various processing stations.
The problem which the invention tries to solve is thus how to join loose optical fibers to form a unified flat structure similar to a ribbon cable or ribbon fiber which can be easily handled for for example splicing.
Optical fibers located parallel to each other in a plane are fixed in this position by tape pieces or strips of tape provided with an adhesive on their surfaces facing the fibers so that the tape pieces are located exactly opposite each other on both sides of the parallel fiber assembly. The tape pieces can extend exactly up to the longitudinal or outer, lateral sides or edges of the assembly but can advantageously be somewhat longer so that adhesives from the opposite tape pieces come in contact with each other at the longitudinal edges of the assembly. The tape pieces are advantageously cut from specially designed retainer or holder tapes which have openings arranged in pairs, the openings of each pair being placed opposite each other at each of the longitudinal or lateral edges of the tape. The assembly is placed so that it extends over the two openings of a pair of each tape, transversely or perpendicularly to the longitudinal direction of the tape. Then the tapes are cut off or more particularly two cuts are made in the tapes only between the openings of the pairs, from one opening of a pair to the other opening of the same pair. Then a piece of each tape located between the openings is separated and adheres to the assembly joining the fibers to form a unit which can be easily and comfortably handled.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the methods, processes, instrumentalities and combinations particularly pointed out in the appended claims.